The present invention relates to wire cable winch hoist controllers used with multi-story scaffolding and, more specifically, to such hoist controllers in which any segment of the cable used therewith may be positioned within the mechanism thereof when the initial assembly of a hoist system occurs at a work site.
While cable winches and controllers therefore are well known in the art as, for example, is reflected in U.S. Pat. No. 5,288,029 (1959) to Tollefsen, entitled Portable Scaffolding; U.S. Pat. No. 3,110,199 (1963) to Lilly, entitled Hoist Controller; and U.S. Pat. No. 3,949,969 (1976) to Kaufer, entitled Cable Winch, an area of inconvenience which is common to these, and other prior art (for example the TIRAK product of Grip Hoist, Inc. and the PC1 product of Power Climber Inc.), is that, in the setting-up and positioning, of the cable hoist controller at a work site, which typically comprises a multi-story structure of between four and dozens of floors, requires that one end of the wire cable of the hoist system be threaded into circumferential grooves which exist upon the driving sheaves which constitute the internal gear and pulley system which substantially all cable hoist controllers, in one configuration or another, use in the elevation and descent of suspended scaffolding, staging and the like.
Therefore, while prior art systems are satisfactory in their operation, once they have been properly set-up, it has been found by the within inventor that the period of time required to accomplish set-up of a cable winch and its associated controller for use with suspended scaffolding or staging can be substantially reduced with a system in which it is not necessary to begin the set-up process with the use of one of the ends of the cable used with the hoist system. The present invention may thereby be viewed as one that can be assembled on site with the use of any segment of the lifting cable that is accessible to the operator.
A further deficiency in the prior art to which the present invention responds is the use of drums upon which a wire cable is wound. After such a cable has been fully, or even partially wound upon a drum, the resultant weight is considerable, thereby impacting upon the safety and convenience in the use of such systems. The instant invention dispenses entirely with the use of any drum and with the use of any type of element which accumulates the wire cable thereon.
Further, the prior art of non-drum systems makes use of typically three sheaves in a controller. The present invention requires only one sheave because of the enhanced traction and safety factors associated therewith.